HTHS vis spec trumps the Kinematic 100C vis spec'

[FoxS]

Originally Posted By: CATERHAM
I'll give an example.
The Idemitsu SM 0W-20 has a 200 VI, the Nippon Oil made Toyota 0W-20 a 214 VI and Sustina 0W-20 a 229 VI. All three oils have the same 2.6cP HTHSV @150C but the Toyota oil is lighter at normal operating temp's than the lower VI Idemitsu oil and the very high VI Sustina is lighter than the Toyota oil.
I'm running the Sustina oil but I want to maintain the same hot operational viscosity as the Idemitsu oil. To do so I've had to increase the HTHSV to approximately 2.75cP (by adding just over 10% of Sustina 0W-50). The end result is that I have an oil that is still lighter on start-up to the other two oils although I'm running a higher HTHSV rated oil; the best of both worlds.


So if I understand this correctly, you've used a higher VI oil to give yourself more headroom.

Very clever application of the technology.

I guess it means that as the Japanese go thinner, they also increase their VI which increases their headroom.

 

[CATERHAM]

Developing higher VI 20wt oils while maintaining the minimum 2.6cP HTHSV for the grade has been the only way to specify a lighter oil under the current SAE grading system; there are no API or ACEA grades officially lighter than SAE 20.
Now that the new SAE 16 grade has been approved, it will be interesting to see what the VI will be of the new 0W-16 grade when Honda and Toyota release their OEM versions. They are already using 4cSt base oils to formulate the highest 220 VI 0W-20s. Base oils lighter than that are not that readily available particularly with a NOACK still less than 15%.
I'm looking forward to seeing the OEM 0W-16 viscosity spec's when they become available.

 

[tudorart]

Originally Posted By: kr_bitog
Originally Posted By: CATERHAM

To pick the ideal oil in terms of viscosity you want an oil with both the highest HTHSV and VI rating that still provides the minimum optimum operational viscosity when the oil is fully hot.

isn't that typically refer to kv100 ?


The industry consensus is that kinematic viscosity measured at 100°C does not relate to engine wear and protection. The parts of the engine most susceptible to wear operate in high temperature, high shear conditions.

The only time Kvis@100C would be a reliable piece of information would be when running polymer free oils.

Operational viscosity in it's most severe form is closest matched by the HTHS vis@150C test. Normal running op visc. should be less that 150 and AFAIK can be as much as 40C difference from engine to engine all things being equal but to this day is still closest matched by the same HTHS test...you just have to adjust for the temperature difference.


You can do a fair guess of your op viscosity by a no. of factors like thermostat opening temp, running oil temp, combined with factory oil HTHS and VI, however oil pressure is a much more reliable and DIRECT indicator...just like CATERHAM clearly stated in his posts on the topic.

 

[blackman777]

So bottom line:

The thin viscosity at 100C is more important then the hths. Right? Is that the conclusion reached?

 

[[RT] ProjUltraZ]

no, the key argument Caterham is making is that HTHS trumps 100C kinematic for determining proper viscosity

 

[blackman777]

Ooops. Thought this was about looking at HTS or 100C viscosity to determine which has best fuel economy.

 

[uzun]

Guys, I would like to resurrect this great thread and shift the discussion toward motorcycle oils if you don't mind.

The manufacturer of my motorcycle (KTM Super Duke 1290 R) recommends the Motorex 10W-50 for all ambient temps above 32F. The specs of this oil can be found at:

http://www.scooter-center.com/medias/sys_master/8865913634846/Powersynt%204t%205w40%20(MX41102).pdf.pdf

Scroll all the way to the end of that document for the English version.

This oil has a VI of 164 and an HTHS specified as >3.5. Do you think the ">3.5" means this oil barely meets the minimum HTHS requirement for a 50 weight?

I am considering Motul 300V 4T 5W-40 as a suitable replacement. The specs of this oil are at:

https://s3-eu-west-1.amazonaws.com/motul....pdf?1492017604

This oil has a VI of 182 and an unspecified HTHS. The car version of this 5W-40 has an HTHS of 4.1. I am assuming the motorcycle version HTHS should be similar.

If what I learned from this thread is correct, I think the Motul 5W-40 would be thicker than Motorex 10W-50 at operating temps because of the higher HTHS and should also be thinner at startup because of the higher VI. So it should be a safe alternative and perhaps better oil for my motorcycle. Do you guys agree?

The motor in question is a shared sump design by the way.

 

[nap]

I would say stick with the original recommendation especially due to the shared sump design.

A few remarks:

In the motorcycle world, you may expect the manual to have a honest recomandation based on engineering data, i.e. not biased by some administrative / business decision (like it’s suspected be the case with car oils in North America).

High VI may not necessarily be a good thing. There’s a recent thread about Nissan research. Some posters in the thread suspect that while a high VI oil could work equally well as low VI oils in journal/bearing applications, the same not be true for other stuff like timing chains or valve trains.

Also subzero temperatures oil performance (where VI may count) may not be relevant to motorcycles, as few would drive them in such temperatures.

And finally motorcycle oils use to be formulated rather differently than their car counterparts, I wouldn’t extrapolate characteristics from one to the other.

 

[A_Harman]

Originally Posted By: uzun
Guys, I would like to resurrect this great thread and shift the discussion toward motorcycle oils if you don't mind.

The manufacturer of my motorcycle (KTM Super Duke 1290 R) recommends the Motorex 10W-50 for all ambient temps above 32F. The specs of this oil can be found at:

http://www.scooter-center.com/medias/sys_master/8865913634846/Powersynt%204t%205w40%20(MX41102).pdf.pdf

Scroll all the way to the end of that document for the English version.

This oil has a VI of 164 and an HTHS specified as >3.5. Do you think the ">3.5" means this oil barely meets the minimum HTHS requirement for a 50 weight?

I am considering Motul 300V 4T 5W-40 as a suitable replacement. The specs of this oil are at:

https://s3-eu-west-1.amazonaws.com/motul....pdf?1492017604

This oil has a VI of 182 and an unspecified HTHS. The car version of this 5W-40 has an HTHS of 4.1. I am assuming the motorcycle version HTHS should be similar.

If what I learned from this thread is correct, I think the Motul 5W-40 would be thicker than Motorex 10W-50 at operating temps because of the higher HTHS and should also be thinner at startup because of the higher VI. So it should be a safe alternative and perhaps better oil for my motorcycle. Do you guys agree?

The motor in question is a shared sump design by the way.


I hate it when spec sheets just list >3.5 for HTHS. The Motorex sheet also lists >3.5 for the 5w40. I would assume that the 10w50 has HTHS significantly higher than the 5w40, and also far above 3.5.

Now here's a stout oil:
https://www.redlineoil.com/10w40-motorcycle-oil

HTHS of 4.7 is explicitly listed, and it has a VI equivalent to the Motorex.
Redline oils are typically lower cost than Motul 300V.

 

[JAG]

I would stick with the Motorex because:
- It is the recommendation...not that I always defer to them
- It has an excellent low volatility
- It has a lower VI, in contrast to the high VI of the Motul oil that is way higher than PAO and/or esters can provide, indicating a large dose of VIIs that will get torn up.
- It has a higher density than the Motul, that along with the provided viscometrics, makes me think that it likely has a higher HTHS than the Motul. Density tends to go up as base oil viscosity goes up, and base oil viscosity is the main driver of HTHS.

I know nothing about the additive package in the Motorex oil. I just focused on other considerations.

 

[BrocLuno]

Yeah, but 300V does work well in the desert. So does Redline, but for the old XL350 Honda, I have found the 300V to be the better choice

 

[ZeeOSix]

Originally Posted By: nap
High VI may not necessarily be a good thing. There’s a recent thread about Nissan research. Some posters in the thread suspect that while a high VI oil could work equally well as low VI oils in journal/bearing applications, the same not be true for other stuff like timing chains or valve trains.


From this reference: http://www.kewengineering.co.uk/Auto_oils/oil_viscosity_explained.htm

Benefits of high VI:

"There are two benefits to a higher VI oil. Not only is the oil thinner when cold, but it is thicker
when warm. A higher VI oil can only be of benefit to a car owner living in a cold climate in Winter
months."


Drawback of high VI - and probably why a lower VI works better in engines that shear oil more:

"However, these VI Improver additives are susceptible to shearing damage from the mechanical
components and would lose some of their performance, resulting in 20W50 oil acting more like
15W40 oil. This damage can happen very early in the life of the oil and is seen as part of the
bedding in of the oil following an oil change. This is why the oil pressure often appears to have
improved just after a fresh oil change as the oil is yet to bed in so is consequently thicker giving a
false impression of improved oil pressure."

 

[zeng]

While there is a basis to your assuming Motorex 10W50 hths be lower than 4.1 cP, however looking at its KV@150*C 69 cSt in relation to Motul 5W40's 56 cSt other than being 10W50 vs 5W40 .....
I 'believe' Motorex 10W50 Hths@150*C could be higher than 4.1 cP and would speculate it to be 4.5ish cP or higher.

 

[dailydriver]

Originally Posted By: JAG
It has a lower VI, in contrast to the high VI of the Motul oil that is way higher than PAO and/or esters can provide, indicating a large dose of VIIs that will get torn up.


Agreed, but given that mostly PAO/POE base stock Motul uses in their 300V line up, they probably did NOT have to add much VII to get to 'just' 182 (IF it were a REALLY high VI, like >210, then yes A BUNCH would have been needed).

We also can guess (or hope?) that Motul uses ONLY the best, most shear proof, 'latest and greatest' VIIs (which everyone and their great grand auntie on here HATED ON, and ragged on CATERHAM for even bringing to light) in their 300V line due to it being a premium, high end, boutique product, but then again who knows.

 

[JAG]

dailydriver, the VI of PAOs in 4 to 10 cSt varieties tends to be around 140-145 and esters of same visosity tend to be in the 130s or less. Getting to over 180 takes quite a bit of VII. The Russian oil forum’s VOAs of 300V has low oxidation values, indicating that only a small amount of esters are used. Quite disappointing.

 

[dailydriver]

Originally Posted By: JAG
dailydriver, the VI of PAOs in 4 to 10 cSt varieties tends to be around 140-145 and esters of same visosity tend to be in the 130s or less. Getting to over 180 takes quite a bit of VII. The Russian oil forum’s VOAs of 300V has low oxidation values, indicating that only a small amount of esters are used. Quite disappointing.


Is there anything in the MSDS of oils which would indicate the TYPE/GRADE of VIIs being used (along with the content percentage), or does that become much less of an 'issue' for low(er) VI number, but majority PAO/POE base stock content oils?

(Example; the Ravenol REP I'm using has a stated 165 VI, and claims a majority PAO/POE base stock, combined with a 6.2% NOACK, and a -60*C pour point. Should I take for granted that they added very little of the highest grade VIIs to get that number?

)

 

[Shannow]

That was the problem with CATERHAM's facts...here's a patent for Asterik, so therefore that's in TGMO, and automatically shears stable.

We have zero way of knowing...even the guys on the board who MAKE and DESIGN the oils won't even hint at their formulations.

As JAG says, anything over 140ish has VMs in it.

Using A Harman's technique, we can get a feel for how much VII is added in a formulation, and it's effect in being non-Newtonian at high shear rates, but zero idea of how stable it is.

It's easy to "want to believe" and "take it for granted"...but they aren't facts...that's why CATERHAM got a hard time.

 

[JAG]

dailydriver, the MSDSs don’t show the VIIs, unfortunately. As Shannow said, you can calculate the “Harman Index”, if you know all of the inputs. Doing a VOA and UOA, using a lab that measures the fuel content in the UOA using the GC method, is a good way to see how shear stable it is. I think you would find that the Ravenol oil has good shear stability, since the VI isn’t all that far above the base oil VI. German Castrol used to have a similar VI and it was very shear stable. M1 0W-40 is not very shear stable, which one can expect based on its very high VI of 186. I suspect it also does not use the most shear stable VIIS, for fuel economy (ex. in MB 229.5 test) reasons.

 

[dailydriver]

So then I guess CATERHAM'S old number one fave, the Sustina 0W-20 sheared horribly if you even looked at it the wrong way, no matter HOW HIGH the quality of the VIIs used in it were, or the quality of it's base stock makeup, given it's 229 VI?

(I still have 2 quarts of this stuff in the basement somewhere.

)

 

[Shannow]

Originally Posted By: dailydriver
So then I guess CATERHAM'S old number one fave, the Sustina 0W-20 sheared horribly if you even looked at it the wrong way, no matter HOW HIGH the quality of the VIIs used in it were, or the quality of it's base stock makeup, given it's 229 VI?

(I still have 2 quarts of this stuff in the basement somewhere.

)


Again, you have no idea HOW HIGH the quality of the ingredients are so the point (and the hyperbole that you guys trot out with it) are moot.

As "horribly"...

https://www.bobistheoilguy.com/forums/ubbthreads.php/topics/3157914/Re:_Eneos_Sustina_0W20__6,646_#Post3157914

"12% isn't much"

"M1 0W20 is MASSIVLEY heavier at startup".

(BTW is the little fireside blog you guys used to run still going ?)